main () {

  List carts = [{
     "count": 3,
     "price": 20.35,
     "name": "男士牙刷",
     "selected": true
  },{
     "count": 1,
     "price": 32.57,
     "name": "男士牙刷",
     "selected": false
  },{
     "count": 5,
     "price": 98.34,
     "name": "男士牙刷",
     "selected": true
  },{
     "count": 9,
     "price": 12.68,
     "name": "男士牙刷",
     "selected": true
  }];
  double allPrice = 0;
 var list = carts.where((item) {
    return item["price"] > 80;
  });
  list.forEach((item) {
   allPrice += item["price"] * item["count"];
  });
  print(allPrice.toDouble());
}